Cardi B still has nightmares about her school days.

The 28-year-old rap star is now one of the world's best-selling music artists, but Cardi admits she still has scary flashbacks to her time in school.

She wrote on Twitter: "I hate having nightmares of me failing a test or being back in highschool wit no shoes on in the hallway. It’s the weirdest thing .... Ya get those type of dreams? (sic)"

One of Cardi's followers subsequently admitted to having nightmares about not graduating from school.

And in response, Cardi - who attended Renaissance High School for Musical Theater & Technology in New York - wrote: "YAAAASSS I F****** HATE THOSE TOO.I be having panic attacks in my sleep specially cause I almost didn’t graduate cause of a gym credit IN REAL LIFE ! (sic)"

Asked by another follower to elaborate on her comment, Cardi explained: "You need like 8 gym credits to graduate in NY but I used to skip gym ...I had to attend a HIV awareness marathon for a credit , Saturday gym class and had to pay 80 dollars to for a cpr class my last month in school just for 3 gym credits cause I failed gym 10 & 11 grade. (sic)"

Meanwhile, Cardi recently insisted she's earned the right to talk-up her career achievements.

The rap star also revealed she's already looking forward to her next project.

She wrote: "Let us talk our s*** and brag for a day ,WE DESERVE It ! When it comes to Cardi it’s always something we work hard .We humble we deserve to get big cocky for at least a day .I’m sooo happy!!! I can’t wait for my next project ! (sic)"